Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Thomas Dag Horn, MD

Individual provider Dermatopathology Physician · NPI 1275620320

Thomas Dag Horn, MD is a Dermatology in Boston, Massachusetts. Graduated from University of Virginia School of Medicine in 1982, 44 years ago. Practices with Massachusetts General Physicians Organization Inc, a 3,484-clinician group and accepts Medicare assignment. Licensed in Arkansas.

Years since qualifying
44
Trained at
University of Virginia School of Medicine
Licensed in
AR
In the registry since
2006
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

55 Fruit St
Boston, MA 02114-2621
Phone: (176) 658-9300
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Dermatology Physician (primary) Taxonomy 207N00000X · Licence E-1269 (AR)
Dermatopathology Physician Taxonomy 207ND0900X · Licence E-1269 (AR)

Record details

NPI number1275620320
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedOctober 9, 2006
Last updated in NPPESSeptember 16, 2019
Mailing address55 Fruit St, Boston, MA 02114-2696

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyDERMATOLOGY
Also practisesPATHOLOGY
Medical schoolUNIVERSITY OF VIRGINIA SCHOOL OF MEDICINE
Graduated 1982 (44 years in practice)
Group practice Massachusetts General Physicians Organization Inc — 3484 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

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